I have an SBS2003R2 network with ISA2004 (dual port server, etc)
I'm moving our mail system to a hosted exchange setup external to the local network (all of the DNS is setup and the mailboxes work OK, no mx is pointing to the internal Exchange2003 box)
I have also removed the domains from the recipient policies.
OK I can connect to the hosted exchange server through RPC over http with a PC connected directly on the router (so on the external side of the SBS2003 box)
I can't connect a domain connected PC to the hosted Exchange2010 server using similar methods. What ports etc need opening through ISA2004 to do this please.
I have read that the IP of the remote exchange server needs to be added to the LAT for this but have not been able to verify or obtain any background on this.
Can anyone help please ????